The present invention relates to a sheet finisher and control method thereof, wherein the sheet finisher that receives a sheet with an image formed thereon by an image forming apparatus such as a copier and printer, applies a process of binding to the sheet by means of a binding device, and ejects the sheet to an ejection tray.
In a sheet finisher, the sheets with images formed thereon by an image forming apparatus are stacked by a predetermined stacking means and are formed into a bundle of sheets, which are then provided with a process of binding to create a booklet or a document. This sheet finisher is widely used as a peripheral apparatus connected with an image forming apparatus.
Further, the disclosed sheet finishers include the apparatus provided with a punching means for punching the sheets having been stacked by the stacking means, similarly to the process of binding or stapling the sheets. (Patent Document 3)
A frequently used means for binding a sheet bundle includes a means that uses an apparatus called a stapler for binding the ends of the sheet bundle with a wire staple, and a means for binding by heating the binding tape coated with hot melt type paste and bringing it in contact with the side edge of the sheet bundle (e.g. Patent Document 1).
However, the work performed by a user using the image forming apparatus connected with a sheet finisher having the aforementioned binding means further contains the work of applying a process of binding, and the work of simply ejecting the sheets with images formed thereon, to an ejection tray and stacking them, without applying the process of binding.
The sheet finisher is provided with a sheet conveyance path for leading the sheets coming out of an image forming apparatus to a binding means and then leading the bound sheet bundle to an ejection tray, and a sheet conveyance path for leading the aforementioned sheets directly to the ejection tray, without feeding the sheets to the binding means. Two sheet conveyance paths arranged in such an apparatus causes increased costs and discourages downsizing of the apparatus. For this reason, a proposal has been made to integrate two sheet conveyance paths into device (e.g. Patent Document 2)
Integrating the sheet conveyance paths into one necessarily results in the arrangement of only the sheet conveyance path for leading the sheet to the binding means. In this case, a means of switching the sheet conveyance path is arranged in the vicinity of the binding means. The sheet conveyance path for applying the process of binding and the sheet conveyance path not intended to apply the process of binding are switched in response to the requirements.
In the sheet finisher arranged in the aforementioned configuration, if the work where binding is performed alternates with the work where it is not performed, the bound sheet bundle is ejected to the ejection tray every time binding has completed. After the sheet conveyance path has been switched, the apparatus handles the next process where binding is not performed. Such an operation cycle is repeated. The switching operation frequently repeated drastically reduces the processing capability of the sheet finisher, with the result that the image forming apparatus is placed in the operation wait status more frequently.
Patent Document 1 denotes Official Gazette of Japanese Patent Application Tokkaihei 7-89259, Patent Document 2 denotes Official Gazette of Japanese Patent Application Tokkaihei 9-240909, and Patent Document 3 denotes Official Gazette of Japanese Patent Application Tokkaihei 5-105308.